Sterile medical liquids such as 5% dextrose, normal saline, sterile water, etc., are often bottled and sterilized by manufacturers and then shipped to hospitals. When ready for use these bottles are opened to dispense sterile irrigating liquids to a surgical wound, or to deliver intravenous liquid into a patient's vein.
A very critical portion of these sterile medical liquid containers is their closure system which protects the dispensing outlet of these containers. Such a closure system must maintain the sterility of the dispensing outlet.
It has been proposed in the past to use double closure systems in which an outer closure fits over and protects a sterile inner closure of the container. In some situations it is desirable to separately remove the outer closure from the inner closure. Then in a subsequent step all or part of the sterile inner closure can be removed to dispense the sterile medical liquid from the container. Sometimes the inner closure is replaceable or reclosable when only a portion of the bottle's contents are dispensed.
While these previous double closure systems with an outer closure separable from the inner closure performed the primary function of protecting the sterility of the dispensing outlet, they were often hard to open. This was because the outer closure required some unusual hand movements and an unusual sequence of steps that the nurse or physician had to remember.